The knowledge imperfections should be considered when modeling complex problems. A solution is to develop a model that reduces the complexity and another option is to represent the imperfections: uncertainty, vagueness and incompleteness in the knowledge base. This paper proposes…

In this note, I propose two extensions to the Java virtual machine (or VM) to allow dynamic languages such as Dylan, Scheme and Smalltalk to be efficiently implemented on the VM. These extensions do not affect the performance of pure…

Object-oriented frameworks are, perhaps, the most important reuse technology today available. This is so, because they enable the reuse of both code and design. However, the effective use of frameworks to instantiate new applications represents one of the most limiting…

The paper describes a framework for the implementation of an elearning system based on the Semantic Web, using software agents and Java Web Services. Hopefully we have elucidated the enormous potential of making web content machine-understandable. One of the killer…

Region-based memory management offers several important advantages over garbage-collected heap, including real-time performance, better data locality and efficient use of limited memory. The concept of regions was first introduced for a call-by-value functional language by Tofte and Talpin, and has…

In this paper a methodology for accesing scientific data repositories on data grids is proposed. This methodology is based on ontology specification and knowledge representation. The concept of Knowledge Perspective is introduced, as the action of applying particular scientific conjectures…

The rising complexity of distributed computer systems give reason to investigate self-organization mechanism to build systems that are self-managing in the sense of Autonomic and Organic Computing.
In this paper we propose the Artificial Hormone System (AHS) as a general…

During a system’s life cycle, new requirements or changes in the existing ones imply modifying the system. Aspect-oriented software development is a new approach to the modularization of systems, yet it does not provide mechanisms to aid the evolution of…

Java 1.5 will include a type system (called JSR-14) that supports parametric polymorphism, or generic classes. This will bring many benefits to Java programmers, not least because current Java practise makes heavy use of logically-generic classes, including container classes. Translation…

In this work an optics virtual laboratory is presented. This virtual laboratory is a set of different applets, tools based in Java, which allow the visualization of different physical laws in the field of optics. The applets have the advantage…